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Atomic Scientists
Important Scientists of the Atom
Scientist | Importance |
---|---|
Democritus | [Philosopher] (460 B.C.-370 B.C.) A greek philopsoper who was one of the first to believe in the existence of Atoms. He believed atoms were INDIVISBLE and INDESTRUCTIBLE. Did not explain chemical behavior. |
John Dalton | (1766-1844) English Chemist who created Dalton's atomic theory based on experimental methods. |
Dalton's atomic theory Pt. 1 | 1. All elements are composed of tiny INDIVISBLE particles called atoms 2. Atoms of the same elemental are IDENTICAL. The atoms of any one element are different from those of other elements. |
Dalton's atomic theory Pt. 2 | 3. Atoms of different elements can be combined phyiscally/ chemically to make simple whole-number ratios to form compounds. 4.Chemical reactions occur when atoms are seperated, joined, or rearanged. Atoms of one element are never changed into other atoms |
J.J. Thomson | (1856-1940) An English physicist who in 1897 discovered the ELECTRON via the Cathode Ray experiment. A cathode ray is an glowing green light that made of electrons {negatively charged}. Also concluded that Charge/mass ration was the same with varied gases |
Robert A. Millikan | (1868-1953) A U.S. Physicist who in 1916 reported the MASS of an ELECTRON very close to the one accepted today (1/1840 of a Hydrogen Atom). |
Eugen Goldstein | (1850-1930) A scientist who discovered PROTONS is 1886 when he noticed a ray running opposite to the Cathode Rays. |
James Chadwick | (1891-1974) An English physicist who in 1932 confirmed the existence of the NEUTRON. |
Ernest Rutherford | (1871-1937) A scientist who conducted the GOLD FOIL EXPERIMENT. This experiment debunked the previous "plum-pudding model" proposed by J.J.Thomson and created evidence for an Atom's NUCLEUS. Using this he created the Rutherford ATOMIC MODEL/Nuclear atom. |